Sam has a total of 58 DVD's and CD's. If the number of CD's is two more than three times the number of DVD's, how many CD's does he have?

Question

anonymous · Answer

dvd + cd = 58
cd + 2 = 3 * dvd

subtract these two equastions
dvd - 2 = 58 - 3 * dvd
dvd = 60 - 3 * dvd
4 * dvd = 60
dvd = 15

so cd = 43

anonymous · Answer

it has to either 42 or 44 not 43

anonymous · Answer

it should be 43 cds and 15 dvds. both of those satisfy the two equations I wrote on the top

anonymous · Answer

idk what i got was 44

anonymous · Answer

Let D be the number of DVDs. Then C, the number of CDs is

C = 3D + 2

The total is 58, so

C + D = 58

3D + 2 + D = 58

4D = 56

D = 14

C = 3(14) + 2 = 42 + 2 = 44

So he has 14 DVDs and 44 CDs